Subject: Re: [PATCH] mm: fix page_mkclean_one (was: 2.6.19 file content
	corruption on ext3)
From: Martin Schwidefsky <schwidefsky@de.ibm.com>
Reply-To: schwidefsky@de.ibm.com
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@osdl.org>, Martin Michlmayr <tbm@cyrius.com>,
       Hugh Dickins <hugh@veritas.com>, Nick Piggin <nickpiggin@yahoo.com.au>,
       Arjan van de Ven <arjan@infradead.org>,
       Andrei Popa <andrei.popa@i-neo.ro>, Andrew Morton <akpm@osdl.org>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
       Florian Weimer <fw@deneb.enyo.de>,
       Marc Haber <mh+linux-kernel@zugschlus.de>,
       Heiko Carstens <heiko.carstens@de.ibm.com>,
       Arnd Bergmann <arnd.bergmann@de.ibm.com>, gordonfarquharson@gmail.com
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Content-Type: text/plain
Organization: IBM Corporation
Date: Thu, 21 Dec 2006 10:26:15 +0100
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On Thu, 2006-12-21 at 10:20 +0100, Peter Zijlstra wrote:
> > Now you are flushing the tlb twice. ptep_clear_flush clears the pte and
> > flushes the tlb, ptep_establish sets the new pte and flushes the tlb.
> > Not good. Use set_pte_at instead of the ptep_establish.
> 
> Yeah, sorry, I already noticed and corrected that :-|
> 
> Also, I'm dubious about the while thing and stuck a WARN_ON(ret) thing
> at the beginning of the loop. flush_tlb_page() does IPI the other cpus
> to flush their tlb too, so there should not be a SMP race, Arjan?

The while loop is protected by the pte lock and flush_tlb_page has to
remove the tlbs on all cpus. So yes, I think the while loop is not
necessary.

-- 
blue skies,
  Martin.

Martin Schwidefsky
Linux for zSeries Development & Services
IBM Deutschland Entwicklung GmbH

"Reality continues to ruin my life." - Calvin.


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